Visual inspection apparatus, visual inspection method, and peripheral edge inspection unit that can be mounted on visual inspection apparatus.

ABSTRACT

This visual inspection apparatus has a macro-inspection section and a micro-inspection section. In the micro-inspection section, a inspection stage and a microscope are loaded into a loading plate. The inspection stage can be moved in any directions of the X, Y, and Z directions, and can also be rotated in the θ direction. Moreover, a peripheral edge inspection section that acquires an enlarged image of a peripheral edge of wafer W is fixed to the loading plate. The peripheral edge inspection section is arranged so as to image the peripheral edge of wafer W held by the inspection stage.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Continuation Application of U.S.application Ser. No. 11/977,880 filed Oct. 26, 2007, which isincorporated herein by reference and which is a Continuation ofInternational Application No. PCT/JP2006308759 filed Apr. 26, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a visual inspection apparatus used toinspect the appearance of a workpiece, a visual inspection method, and aperipheral edge inspection unit that can be mounted on such a visualinspection apparatus and used to inspect the peripheral edge of theworkpiece.

2. Description of Related Art

When patterns, such as circuits, on a workpiece, such as a semiconductorwafer, are formed, a visual inspection apparatus that inspects theexistence of a defect on the surface of the workpiece is used. As thistype of visual inspection apparatus, there is an inspection apparatus(for example, refer to Patent Document 1) that oscillates and rotatablyholds a workpiece, has a macro-inspection section that allows aninspector to visually inspect the surface of the workpiece (macroinspection), and a micro-inspection section that acquires an enlargedimage of the workpiece to allow inspection (micro inspection), and thatenables such macro inspection and micro inspection by use of oneapparatus.

Further, when circuits, etc. are formed on a workpiece, warpage orinternal stress may be caused in the workpiece due to heat treatment,etc. If such warpage and internal stress become large, the workpiece maybe fractured during manufacture of the circuits. Thus, a technique ofenlarging and observing the peripheral edge of the workpiece in advance,thereby inspecting the existence of cracks which may becomes fracturesin the future, is known. As a visual inspection apparatus used toinspect the peripheral edge of the workpiece (peripheral edgeinspection), there is an inspection apparatus (for example, refer toPatent Document 2) including a support that rotatably supports aworkpiece, a peripheral edge imaging section that continuously capturesimages of the peripheral edge of the workpiece, and a peripheral edgeillumination device that illuminates the peripheral edge.

[Patent Document 1] JP-A-2004-96078

[Patent Document 2] JP-A-2003-243465

However, in order to carry out the macro inspection, micro inspection,and peripheral edge inspection, there are problems in that a wafer mustbe replaced and moved by a machine, a loader, etc., between the visualinspection apparatus disclosed in Patent Document 1, and the visualinspection apparatuses disclosed in Patent Document 2, causing prolongedtakt time. Further, when one visual inspection apparatus is attached toanother visual inspection apparatus externally, transport time can beshortened. However, replacement of a workpiece is required even in sucha case. Moreover, the installation area as the whole apparatus is notdifferent from when apparatuses are installed independently.

SUMMARY OF THE INVENTION

The invention has been made in view of the above circumstances. It istherefore a main object of the invention is to reduce takt time,miniaturize the apparatus, and simplify the configuration of theapparatus in performing macro inspection, micro inspection, andperipheral edge inspection.

In order to solve the above problems, the invention provides a visualinspection apparatus including: a visual inspection section forperforming visual inspection of the surface of a workpiece, and aperipheral edge inspection section that acquires an enlarged image of aperipheral edge of the workpiece. Here, a holding unit that holds theworkpiece in the visual inspection section is shared by the visualinspection section and the peripheral edge inspection section.

Further, the invention provides a visual inspection method including:holding a workpiece by a holding unit and inspecting the appearance ofthe surface of the workpiece; bringing a peripheral edge inspectionsection that acquires an enlarged image of a peripheral edge of theworkpiece relatively close to the holding unit; and acquiring theenlarged image of the peripheral edge of the workpiece in a state wherethe holding unit is brought relatively close to the peripheral edgeinspection section.

In the invention, when visual inspection is performed, a workpiece isheld by the holding unit, and inspection is performed while the holdingunit is moved as needed. Moreover, when the peripheral edge inspectionis performed, a workpiece is rotated while the workpiece is held by theholding unit without performing transfer of the workpiece, and theenlarged image of a peripheral edge of the workpiece is acquired in theperipheral edge inspection section.

Moreover, the invention provides a peripheral edge inspection unitmountable on the visual inspection apparatus including: an anchor thatis detachable to a visual inspection section that allows visualinspection of the surface of a workpiece in a state where the workpieceis movably held by a holding unit; and an enlarged image acquisitionpart that is arranged so as to face a peripheral edge of the workpieceheld by the holding unit, and is capable of acquiring an enlarged imageof the peripheral edge of the workpiece.

In the invention, it is possible to fix the anchor to a predeterminedposition of the visual inspection section, thereby performing theperipheral edge inspection, using the holding unit of the visualinspection section. That is, visual inspection can be performed, withouttransferring a workpiece carried into the visual inspection section.Here, the peripheral edge refers to a side part, and a chamfered part ofa workpiece, and a surrounding part of its front and back surfaces.Further, if the workpiece is a wafer, an edge cut line portion after anunnecessary resist is removed after application of a resist is includedin the peripheral edge.

According to the present invention, in the visual inspection apparatusthat has the visual inspection section that is used to allow visualinspection of the surface of a workpiece, the holding unit that holdsthe workpiece is shared by the visual inspection of the surface of theworkpiece, and the peripheral edge inspection that inspects theperipheral edge of the workpiece. Thus, it is possible to perform thevisual inspection and peripheral edge inspection while the workpiece isheld by the holding unit, without performing transfer of the workpiece.Furthermore, compared with a case where apparatuses are configuredindependently, the installation area can be made small. Moreover, sincethe distance at which the workpiece is moved, and the time and effortfor transfer can be omitted, the tact time of inspection can be reduced.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a plan view showing the schematic configuration of a visualinspection apparatus according to an embodiment of the invention

FIG. 2 is a side view showing the schematic configuration of the visualinspection apparatus

FIG. 3 is an exploded view illustrating attachment and detachment of aperipheral edge inspection section FIG. 4 is a plan view showing theschematic configuration of the visual inspection apparatus

FIG. 5 is a side view showing the schematic configuration of the visualinspection apparatus

FIG. 6 is a side view showing the schematic configuration of the visualinspection apparatus

FIG. 7 is a plan view showing the schematic configuration of the visualinspection apparatus

FIG. 8 is a view showing an exemplary configuration when a variabledirection-of-view observation apparatus of a first mode is seen from thefront of the apparatus

FIG. 9A is a view showing an exemplary configuration when the variabledirection-of-view observation apparatus of the first mode is seen fromthe side of the apparatus

FIG. 9B is a view showing an exemplary configuration of a mirror cam asseen from an arrow A1 side in FIG. 9A

FIG. 10A is a view for explaining an observable direction of view in thevariable direction-of-view observation apparatus of the first embodiment

FIG. 10B is a view for explaining the observable direction of view inthe variable direction-of-view observation apparatus of the firstembodiment

FIG. 11 is a view showing an exemplary configuration when a variabledirection-of-view observation apparatus of a second embodiment is seenfrom the front

FIG. 12A is a view showing an exemplary configuration when a variabledirection-of-view observation apparatus of a third embodiment is seenfrom the front

FIG. 12B is a view showing an exemplary configuration when the variabledirection-of-view observation apparatus of the third embodiment is seenfrom the back FIG. 12 C is a view showing a cross-sectional exemplaryconfiguration of a movable front-and-back observation mirror as seenfrom an arrow C1 side in FIG. 12B;

FIG. 13A is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment

FIG. 13B is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment

FIG. 13C is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment

FIG. 13D is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment

FIG. 13E is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment

FIG. 13F is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment

FIG. 13G is a view for explaining the operation of the variabledirection-of-view observation apparatus of the third embodiment.

REFERENCE NUMERALS

-   -   1, 51, 71: VISUAL INSPECTION APPARATUS    -   10: MICRO-INSPECTION SECTION (VISUAL INSPECTION SECTION)    -   11: MICRO-INSPECTION SECTION (VISUAL INSPECTION SECTION)    -   12, 61: PERIPHERAL EDGE INSPECTION SECTION (PERIPHERAL EDGE        INSPECTION UNIT)    -   15, 30, 72: LOADING PLATE    -   22: MICRO-INSPECTION UNIT (HOLDING UNIT)    -   31, 74, 95: INSPECTION STAGE (HOLDING UNIT)    -   36A, 79: ROTARY SHAFT    -   41: ANCHOR    -   44: ENLARGED IMAGE ACQUISITION PART    -   45, 96: CONTROL DEVICE    -   73: AUTOMATIC MICRO-INSPECTION SECTION (VISUAL INSPECTION        SECTION)    -   W: WAFER (WORKPIECE)    -   101: BASE    -   101 a: MOTOR ATTACHING PLATE    -   102: MOTOR    -   103: BALL SCREW SET    -   103 a: BALL SCREW    -   103 b: BALL SCREW GUIDE    -   104: Z-DIRECTION MOVABLE LINEAR GUIDE    -   104 a, 106 a: RAIL    -   104 b, 106 b: CASE    -   105: Z-MOVABLE CARRIAGE    -   105 a: ARM    -   106: X-DIRECTION MOVABLE LINEAR GUIDE    -   107: X MOVABLE PLATE    -   108: CAM    -   108 a, 118 a: CAM SURFACE    -   109, 117: CAM ROLLER    -   111, 120: TENSION SPRING    -   112: CCD CAMERA    -   114: WAFER    -   115: ROTARY MIRROR    -   116: ROTARY SHAFT    -   118: MIRROR CAM    -   119: ROTARY ARM    -   121 a, 121 b: SPRING HOOK    -   122: IMAGING LENS    -   200, 201, 202: VARIABLE DIRECTION-OF-VIEW OBSERVATION APPARATUS        (PERIPHERAL EDGE INSPECTION SECTION)

DETAILED DESCRIPTION OF THE INVENTION

The best modes for carrying out the invention will be described indetail with reference to the accompanying drawings.

First Embodiment

As shown in FIG. 1, a visual inspection apparatus 1 has an inspectionsection 2 provided at the front (a lower part in FIG. 1) that faces aninspector, and a loader part 3 is connected to the back side of theinspection section 2. In the loader part 3, two wafer carriers 4A and 4Bthat receive semiconductor wafers W (hereinafter referred to as “waferW”) that are workpieces are connected side by side. In addition, thewafer carriers 4A and 4B can receive a plurality of wafers W at apredetermined pitch in a vertical direction. For example, anon-inspected wafer W is received in the wafer carrier 4A, and aninspected wafer W is received in the wafer carrier 4B. Moreover, thewafer carriers 4A and 4B can be independently attached to and detachedfrom the loader part 3.

The loader part 3 has an automated transport unit 5. The automatedtransport unit 5 includes a multi-segmented robotic arm, and a hand 5Aat a tip of the robotic arm is provided with suction holes 6 that holdwafer W by suction-clamping. This automated transport unit 5 isconfigured movably and rotatably so that the wafer W can be transportedbetween each of the two wafer carriers 4A and 4B and a macro-inspectionsection 10 of the inspection section 2.

The inspection section 2 has an the macro-inspection section 10 that isused in order for an inspector to inspect the surface of wafer Wvisually and macroscopically (macro inspection), and a micro-inspectionsection 11 that makes an inspection (micro inspection) performed byacquiring an image of the surface of wafer W as an enlarged image of ahigher magnification than visual observation, and a peripheral edgeinspection section 12 that acquires an enlarged image of a peripheraledge of wafer W is attached to the micro-inspection section 11.

In the macro-inspection section 10, a swivel arm 16 is rotatably andliftably provided on the loading plate 15. The swivel arm 16 has threetransport arms 18, 19, and 20 horizontally extending equiangularly froma rotary shaft 17, and a plurality of suction holes (wafer chuck) 21 areprovided at the tip of each of the transport arms 18, 19, and 20. Thesesuction holes 21 are connected to a suction device that is not shown.Moreover, the rotation of the swivel arm 16 is controlled so that thetransport arms 18, 19, and 20 may be arranged at positions P1, P2, andP3, respectively. The position P1 is a transfer position where wafer Wis transferred between the macro-inspection section 10 and the loaderpart 3, and the position P2 is an inspection position where macroinspection is performed. The position P3 is a transfer position wherewafer W is transferred between the macro-inspection section 10 and themicro-inspection section 11.

In addition, a macro-inspection unit 22 is provided in the position P2.The macro-inspection unit 22 has a base part 23 fixed to the loadingplate 15. A holder 24 that holds wafer W by suction-clamping is providedin the base part 23 so as to be liftable and oscillatable in the Zdirection (vertical direction), and causes the wafer W in the positionP2 to rise towards an inspector so that the wafer W can be rotated andoscillated. Moreover, an illumination device (not shown) thatilluminates wafer W in the position P2 is provided above the swivel arm16. The illumination device is configured by, for example, a lightsource, and an optical system that can switch between irradiating awafer W with illumination light as scattered light and irradiating thewafer W with the illumination light as condensed light. Further, aposition detecting sensor 50 that make an alignment of a wafer W isprovided in the position P3. This position detecting sensor 50 detectsthe position of a notch of the wafer W and any positional deviation ofthe center of the wafer W by rotating the wafer W while being placed ona rotating stage 36. If any positional deviation is detected, theposition of the rotating stage 36 is corrected with the wafer W beinglifted by the transport arms 18, 19, and 20 so that the rotation centerof the rotating stage 36 and the rotation center of wafer W may coincidewith each other, and thereafter, the transport arms 18, 19, and 20 arelowered to allow high-precision alignment.

As shown in FIGS. 1 and 2, the micro-inspection section 11 is installedon a loading plate 30 the vibration of which is removed by anappropriate vibration removal mechanism, and has an inspection stage 31that is a holding unit that holds the wafer W, and a microscope 32 thatobserves the wafer W on the inspection stage 31. In the inspection stage31, an X-axis slider 33 that is movable in the X direction shown in FIG.1, and a Y-axis slider 34 that is movable in the Y direction arearranged so as to be stacked vertically. A Z-axis stage 35 that ismovable in the Z direction is provided on the Y-axis slider 34. TheZ-axis stage 35 is provided with the rotating stage 36 as a rotatingmechanism that is rotatable in the θ direction. As shown in FIG. 2, therotating stage 36 has a rotary shaft 36A connected with a motor that isnot shown, and a holder 36B on a disk is fixed to an upper end of therotary shaft 36A. The external diameter of the holder 36B is smallerthan the external diameter of wafer W, and a central portion of theholder is provided with a suction hole (not shown) for sucking wafer W.The suction hole is connected to a suction device that is not shown.

Moreover, in the micro-inspection section 11, the peripheral edgeinspection section 12 is fixed to a front side part of the loading plate30. The peripheral edge inspection section has three enlarged imageacquisition parts each including an imaging optical system, an imagingdevice, such as a CCD, etc., and captures an image of the peripheraledge of the wafer from its top, side, and bottom surface sides. Then,the captured image is displayed on a display unit 60, and is observedand inspected by an inspector. The peripheral edge inspection section 12is located at a position that does not become obstructive when thesurface of the wafer W is observed by the microscope 32 of themicro-inspection section 11, i.e., outside a micro-inspection region Ashown by an imaginary line so as not to interfere with the wafer W atthe time of micro-inspection. As shown in FIG. 3, the peripheral edgeinspection section 12 is a peripheral edge inspection unit that can befreely detached and attached separately from the loading plate 30, andhas an anchor 41 fixed to screw holes 30A of the loading plate 30 withbolts 40. A base part 42 extends in the Z direction from the anchor 41.A recessed part 43 is formed in this base part 42 so as to allowentrance of the peripheral edge of the wafer W. An enlarged imageacquisition part 44 including a microscope that is a magnifying opticalsystem, and a CCD (Charged Coupled Device) is provided in the recessedpart. The enlarged image acquisition part 44 has an enlarged imageacquisition part 44A that observes the upper surface (surface) of theperipheral edge of the wafer W from above, an enlarged image acquisitionpart 44B that observes the peripheral edge of the wafer W from the side,and an enlarged image acquisition part 44C that observes the lowersurface (rear surface) of the peripheral edge of the wafer W from below.In addition, if the enlarged image acquisition part 44 has aconfiguration that can acquire an image, it will not be limited to theCCD. Further, the peripheral edge inspection sections 12 may havevarious configurations, such as a single-eye type including one enlargedimage acquisition part 44 in a movable manner, and a five-eye type inwhich two enlarged image acquisition parts 44 are added so as tosandwich the enlarged image acquisition part 44B from the right andleft. As an example of the single-eye type may include, a configurationin which the direction of an optical axis is fixed, a microscope and amirror that are movable relative to one another in the XYZ directionsare included, and the mirror and the microscope are moved so as to keepthe distance between the microscope and the part of an object to beobserved always constant may be mentioned. This concrete configurationwill be described below as a second modified example. Moreover, asanother example of the single-eye type, a configuration in which onlyone enlarged image acquisition part 44 of the peripheral edge inspectionsection 12 of FIG. 3 is included, and an end of the wafer W rotatesabout the center thereof may be mentioned.

Also, as shown in FIG. 2, the inspection stage 31 and the peripheraledge inspection section 12 are connected to a control device 45. Thecontrol device 45 includes a CPU (Central Processing Unit), a memory,etc., and controls the whole visual inspection apparatus 1. In additionto these, the macro-inspection section 10, the automated transport unit5, and a display device (not shown), such as a display, are alsoconnected to the control device 45.

Next, the operation of the present embodiment will be described.

First, the wafer carrier 4A that has received the wafer W to beinspected, and the empty wafer carrier 4B is mounted on the loader part3. The automated transport unit 5 takes out one wafer W from the wafercarrier 4A, and transfers the wafer to the transport arm 18 in theposition P1 of the macro-inspection section 10. The swivel arm 16rotates with the wafer W being held by suction-clamping by the transportarm 18, and moves the wafer W to the position P2. Here, after the waferW is held and raised by the macro-inspection unit 22 after the suctionof the transport arm 18 is released, the wafer W is made to rise,rotate, and oscillate by an oscillating mechanism.

When the surface of the wafer W has been irradiated with theillumination light from an illumination device, and the existence of adefect, or the state of the defect has been visually checked, the waferW is lowered, and is again held by suction-clamping by the transport arm18. In addition, at this time, the transport arm 20 is arranged in theposition P1 by the rotation of the swivel arm 16. In this case, thefollowing wafer W is placed on the transport arm 20 by the automatedtransport unit 5.

Next, the swivel arm 16 is rotated to move the wafer W in the positionP2 to the position P3, and to move the wafer W in the position P1 to theposition P2. Since the inspection stage 31 stands by in the position P3,the wafer W is transferred from the transport arm 18 to the holder 36Bof the inspection stage 31. In addition, at this time, macro inspectionis performed on the following wafer W that has moved to the position P2,similarly to the above. Further, still another wafer W is placed on thetransport arm 19 that has moved to the position P1.

In the micro-inspection section 11, alignment of the wafer W is made inthe position P2 on the rotating stage 36 of the inspection stage 31, thecontrol device 45 makes the inspection stage 31 move, thereby making thepart of the wafer W to be inspected move into the field of view of anobjective lens 32A (refer to FIG. 2) of the microscope 32. An enlargedimage acquired by the microscope 32 is visually checked as an inspectorlooks into an eyepiece that is not shown. Here, if an imaging device isinstalled in the microscope 32, inspection may be performed, visuallyobserving the display unit 60. When micro inspection has been performedon all objects to be inspected while the inspection stage 31 is moved,the control device 45 makes the inspection stage 31 move obliquelyforward in the XY direction as shown by the arrow B, thereby bringingthe inspection stage 31 closer to the peripheral edge inspection section12 and further making the peripheral edge of the wafer W enter therecessed part 43 of the peripheral edge inspection section 12 whileadjusting the height of the stage.

In the peripheral edge inspection section 12, for example, an image ofthe surface of the peripheral edge of the wafer W is acquired by theupper enlarged image acquisition part 44A, and the acquired imageprocessed by the control device 45, is output to the display unit 60. Inthis case, the control device 45 makes the rotary shaft 36A of theinspection stage 31 rotate, thereby making the wafer W rotate in the θdirection at a predetermined speed. When the existence/non-existence ofa scratch, etc. has been checked by performing single-around inspectionof the peripheral edge of the wafer W in this way, then the peripheraledge inspection is performed similarly to the above by acquiring theimages of the side surface and rear surface of the peripheral edge ofthe wafer W in order by the enlarged image acquisition part 44B and theenlarged image acquisition part 44C. In addition, the enlarged imageacquisition parts 44A, 44B, and 44C may be operated at a same time,thereby simultaneously performing the inspections from three directions.Further, it is desirable that the inspection of the peripheral edge isautomatically performed by image processing. For example, the luminanceinformation of the peripheral edge of a good wafer W, and the luminanceinformation of a wafer to be inspected that is acquired in advance maybe compared with each other. Further, since the luminance of aperipheral edge of only one wafer W becomes constant except a notch, aportion the change of luminance of which has exceeded a fixed value maybe extracted as a defect.

When the peripheral edge inspection has been completed, the inspectionstage 31 is spaced apart from the peripheral edge inspection section 12,and is returned to the position P3 that is a transfer position, and istransferred to the transport arm 18 that stands by in the position P3.The swivel arm 16 rotates the transport arms 18, 19, and 20, and returnsan inspected wafer W to the position P1. The automated transport unit 5carries out the inspected wafer W, and receives the wafer W in the wafercarrier 4B. A non-inspected wafer W is newly transferred to thetransport arm 18 in the position P1 that has become empty. Further, thenext wafer W on which macro inspection has been performed in theposition P2 is carried into the inspection stage 31 in the position P3.Then, when all wafers W as objects to be inspected within the wafercarrier 4A are inspected similarly to the above, the wafer carriers 4Aand 4B are detached, and then the next wafer carriers to be inspectedare mounted.

In addition, in this visual inspection apparatus 1, the shift toperipheral edge inspection is made after micro inspection is completed.However, the shift to micro inspection or peripheral edge inspection maybe made with any timing by control of the control device 45. Moreover,only micro inspection and peripheral edge inspection may be performedwithout performing macro inspection, or only macro inspection andperipheral edge inspection may be performed without performing microinspection.

According to the present embodiment, when visual inspection of the waferW is performed, the peripheral edge inspection section 12 is attached tothe micro-inspection section 11, and the inspection stage 31 of themicro-inspection section 11 is used for both the micro inspection andthe peripheral edge inspection. Thus, the installation area of theapparatus can be made small. Moreover, the peripheral edge inspectioncan be performed without transferring the wafer W from the microinspection, and the traveling distance of the inspection stage 31 canalso be significantly reduced compared with the case where separatedevices are provided. Thus, the takt time required for inspection can beshortened.

Since the peripheral edge inspection section 12 and the inspection stage31 are configured so that they can relatively brought closer to orspaced apart from each other, it is possible to prevent the wafer W,etc. and the peripheral edge inspection section 12 from interfering witheach other during micro inspection. Moreover, since the peripheral edgeinspection section 12 and the inspection stage 31 are provided on thesame loading plate 30, any deviation in the height direction becomessmall, and the height adjustment at the time of peripheral edgeinspection becomes easy. In particular, in the present embodiment,alignment is made with precision when the wafer W is transferred to therotating stage 36. Thus, when wafer W is rotated and inspected in theperipheral edge inspection section 12, any movement caused by rotationof the wafer W in an observation position is suppressed, and aninspection at high magnification is allowed. Further, the positiondetecting sensor 50 detects the amount of deviation between the notchposition and center position of the wafer W in the position P3. Thus, bycontrolling the inspection stage 31 at the time of inspection of aperipheral edge even if replacement of the wafer W is not performed,inspection may be performed in a state where any eccentricity is notcaused when wafer W is rotated.

Further, the screw holes 30A that fix the peripheral edge inspectionsection 12 are bored in the loading plate 30 of the micro-inspectionsection 11, and the peripheral edge inspection section 12 is configuredso as to be attachable to or detachable from the micro-inspectionsection 11 as a peripheral edge inspection unit. Thus, peripheral edgeinspection can be performed only by mounting the peripheral edgeinspection section 12 on a visual inspection apparatus having themacro-inspection section 10 and the micro-inspection section 11. Thatis, the aforementioned effects will be obtained even by the existingvisual inspection apparatus only by its minimum changes. Alternatively,the peripheral edge inspection section 12 may be integrally anchored tothe loading plate 30.

In addition, a uniaxial stage that is movable horizontally in the Bdirection may be provided between the anchor 41 of the peripheral edgeinspection section 12, and the base part 42 so that the base part 42 canadvance or retract in the direction of the wafer W. Even in this case,the same effects as the above can be obtained. Moreover, the takt timecan be further reduced by moving the peripheral edge inspection section12 towards the inspection stage 31. A stage that is interposed betweenthe anchor 41 and the base part 42 is not limited to the uniaxial stage.For example, a biaxial stage that is movable even in a directionorthogonal to the B direction, a triaxial stage that is movable even inthe Z direction, or a biaxial stage that is movable even in the Bdirection and the Z direction may be used satisfactorily. If themicroscope 32 is configured such that the objective lens part 32A ismovable in the Z-axis direction, and the base part 42 is configured soas to be movable in the Z direction, it becomes unnecessary to providethe inspection stage 31 with the Z-axis stage 35. Thus, theconfiguration of the inspection stage 31 can be simplified.

Further, the above embodiment may be modified so as to have a functionto record the coordinate of an observation position when inspection ismade in either one of the micro-inspection section and the peripheraledge inspection section and to move the observation position to anobservation position of the other inspection section on the basis of therecorded coordinate of the observation position when inspection is madein the other inspection section (first modified example). That is, thefirst modified example, as shown in FIGS. 1 and 2, includes aninspection stage 95 that has a configuration similar to the inspectionstage 31, and is adapted to be able to detect the coordinate of theposition of the wafer W in each axial direction of XYZ, instead of theinspection stage 31 of the visual inspection apparatus 1 of the abovefirst embodiment, and includes a control device 96 that has aconfiguration similar to the control device 45, and is adapted to beable to acquire and store the coordinate information on the position ofa wafer detected by the inspection stage 95, and to control of visualinspection apparatus 1 using the coordinate information, instead of thecontrol device 45.

The inspection stage 95 is mounted with, for example, a stepping motor,serving as a power source that drives the X-axis slider 33, the Y-axisslider 34, the Z-axis stage 35, and the rotating stage 36, which areprovided similarly to the inspection stage 31, in their respectivemovement directions. Also, the coordinate of a position to which thewafer W has been moved can be detected on the basis of the informationon the rotation angle of this stepping motor from its referenceposition.

Here, such as actuators, scales, which can detect the coordinates of aposition, a servo motor, a linear scale, and a linear motor, other thanthe stepping motor, etc., can be suitably adopted as the power source ofthe inspection stage 95.

Next, the operation of the first modified example will be described.

While the wafer W put on the inspection stage 95 is moved and theperipheral edge of the wafer W is observed by the microscope 32 as microinspection, in order to find out a defect and check the side surface orrear surface, the shift to peripheral edge inspection is immediatelymade so that the peripheral edge of the wafer W may be observed.

At that time, since the inspection stage 95 can detect coordinates ineach axial direction, an instruction is issued by the operation part 70,like pushing one button, and the coordinate information is stored in thecontrol device 96. Then, when the shift to peripheral edge inspectionhas been made from a point 97 on the optical axis of the objective lensof the microscope 32 that is performing the micro inspection, using thecoordinate information stored in the control device 96, the inspectionstage 95 is controlled by the control device 96 so that the point 97observed by the microscope 32 can be observed as it is even by theperipheral edge inspection section, and thereby the wafer W is moved sothat the point 97 may be located on the optical axis of the imagingoptical system of the peripheral edge inspection section.

After the peripheral edge of the moved wafer W in various optionalpositions has been observed manually by the operation part 70 orautomatically by an observation method that is input and set in advance,the shift to the original peripheral edge observation of the wafer W bythe microscope 32 is made. Specifically, the coordinate information onthe point 97 stored in the control device 96 is used to control theinspection stage 95, and the point 97 that has originally performedvisual inspection of the peripheral edge of the wafer W by themicroscope 32 is moved back to a position where it can be observed bythe microscope 32.

On the contrary, when a defect is detected while the wafer W put on theinspection stage 95 is moved and the peripheral edge of the wafer W isobserved in the peripheral edge inspection, in order to detect and checkthe defect by an enlarged image, the shift to the micro inspection by amicroscope is immediately made so that the peripheral edge of wafer Wmay be observed.

In this case, the coordinates of the point 97 that is performing theperipheral edge inspection by an instruction by the operation part 70 isdetected by the inspection stage 95, and the coordinate information isstored in the control device 96. Then, when the shift to microinspection by a microscope has been made, the inspection stage 95 iscontrolled by the control device 96 so that the point 97 observed by theperipheral edge inspection section can be observed as it is even in theperipheral edge observation of the microscope 32, and thereby the waferW is moved so that the point 97 may be located on the optical axis ofthe microscope 32.

After the peripheral edge of the moved wafer W in various optionalpositions is manually or automatically observed by the microscope, theshift to the original peripheral edge observation by the peripheral edgeinspection section is made. Specifically, the coordinate information onthe point 97 stored in the control device 96 is used to control theinspection stage 95, and the point 97 that has originally inspected theperipheral edge of the wafer W by the peripheral edge inspection sectionis moved back to a position where it can be observed by the peripheraledge inspection section.

Next, the effects of the first modified example will be described.

According to this modified example, if an attempt to observe theperipheral edge of a wafer as well as the surface of the wafer as it isor vice-versa is made while the wafer W put on the inspection stage 95is moved, and the peripheral edge of the wafer W is observed by themicroscope 32, that is, if any shift between the visual inspection andperipheral edge inspection is made, the coordinate information on thepoint that has been observed in each inspection is stored only bypushing one button of the operation part 70, and the wafer W is movedusing the coordinate information. Thus, in each inspection, the sameobservation point can be observed. Therefore, for example, if a scratch,a crack, or the like that runs from the surface of a wafer to theperipheral edge and rear surface thereof is observed, the position ofthe scratch or crack can be observed continuously without any positionaldeviation, in the visual inspection and peripheral edge inspection bythe microscope, observation precision and observation speed can beimproved.

This makes it possible to smoothly and continuously perform visualinspection or peripheral edge inspection of the peripheral edge or othersurfaces of the wafer W.

Second Embodiment

A second embodiment is characterized in that the peripheral edgeinspection section is provided in the macro-inspection section in whichinspection is performed by visual observation. Other configurations andoperations are the same as those of the first embodiment.

As shown in FIG. 4, in a visual inspection apparatus 51, a peripheraledge inspection section 61 (outer edge inspection unit) is detachablyprovided in the loading plate 15 of the macro-inspection section 10. Theperipheral edge inspection section 61 has a anchor 62 fixed to theloading plate 15, a uniaxial stage 63, and a base part 42 attached tothe enlarged image acquisition part 44. The base part 42 is attached sothat it can be brought close to or spaced apart from the position P2. Asshown in FIG. 5, in an inspection position where the base part 42 isbrought closest to the position P2, the peripheral edge of the wafer Wheld horizontally by the macro-inspection unit 22 enter the recessedpart 43. Further, as shown by an imaginary line, in a position when thebase part 42 is most spaced apart from the position P2, the base partretracts from a macro-inspection region C, and will not interfere withthe rotation of the swivel arm 16, and the oscillation of the wafer W bythe macro-inspection unit 22.

Further, the macro-inspection unit 22 is a holding unit provided with arotating mechanism that rotates the wafer W that is held while beingoscillated, other than a lifting mechanism and an oscillation mechanism.

If visual inspection of the wafer W is performed in the presentembodiment, the wafer W conveyed to the position P2 is held bysuction-clamping by the macro-inspection unit 22, and is thenmacro-inspected. When the macro inspection has been completed, the waferW is held horizontally at a predetermined height, and the peripheraledge inspection section 61 is moved to the inspection position. Then,while the wafer W is rotated by the macro-inspection unit 22, peripheraledge inspection is performed similarly to the first embodiment. When theperipheral edge inspection has been completed, the wafer W istransferred to the transport arm 19 from the macro-inspection unit 22after the peripheral edge inspection section 61 retracts to a stand-byposition. Further, the swivel arm 16 is rotated to transfer the wafer Wto the position P3. From here, the wafer W is transferred to themicro-inspection section 11 where micro inspection is performed. Whenthe micro inspection has been completed, the wafer W is returned to theposition P1 via the position P3, and is then received in the wafercarrier 4B.

In addition, in this visual inspection apparatus 51, the shift toperipheral edge inspection is made after macro inspection is completed.However, the shift to macro inspection or peripheral edge inspection maybe preferred at any timing by control of the control device 45.Moreover, only macro inspection and peripheral edge inspection may beperformed without performing micro inspection, or only micro inspectionand peripheral edge inspection may be performed without performing macroinspection.

In the present embodiment, the peripheral edge inspection section 61 isprovided in the micro-inspection section 10, and the macro-inspectionunit 22 of the micro-inspection section 10 is used for both the microinspection and the peripheral edge inspection. Thus, the reducedinstallation area of the apparatus can be achieved. Moreover, theperipheral edge inspection can be performed without transferring thewafer W from the macro inspection, and the traveling distance of theperipheral edge inspection section 61 can also be significantly reducedcompared with a case where separate devices are provided. Thus, the takttime required for inspection can be shortened. In addition, the effectobtained by providing the macro-inspection unit 22 and the peripheraledge inspection section 61 so that they can be brought close to orspaced apart from each other, and the effect obtained by loading themacro-inspection unit and the peripheral edge inspection section on thesame loading plate 15 are the same as those of the first embodiment.Moreover, the effect obtained by configuring the peripheral edgeinspection section 61 so as to be attachable to or detachable from themacro-inspection section 10 is the same as that of the first embodiment.

Third Embodiment

A third embodiment is characterized in that the peripheral edgeinspection section is provided in an automatic micro-inspection sectionthat automatically extracts a defect by image processing from an imagecaptured by an imaging device.

Other configurations and operations are the same as those of the firstembodiment. As shown in FIGS. 6 and 7, a visual inspection apparatus 71has a loading plate 72 that is free from vibration, and an automaticmicro-inspection section 73 is constructed in the loading plate 72. Theautomatic micro-inspection section 73 has an inspection stage 74, and anillumination device 75 and an imaging section 76 fixed so as to sandwichthe inspection stage 74 in the X direction. The inspection stage 74includes an X-axis stage 77, a Z-axis stage 78, and a rotary shaft 79serving as a rotating mechanism, and a holding plate 80 that holds awafer by suction-clamping is fixed on the rotary shaft 79. Theillumination device 75 has a line light source that irradiates the uppersurface (surface) of the wafer W with linear illumination light from theslanting upper side. The line light source extends in the Y-directionorthogonal to the X-direction. Similarly, in the imaging section 76, anoptical system is arranged so as to take an image of the linearreflected light or diffracted light that the illumination light from theillumination device 75 has been reflected by the upper surface of waferW, and imaging devices are arrayed in a line in the Y-direction in theposition of the image. Also, the optical axis of the imaging section 76and the optical axis of the illumination device 75 are arranged so as tointersect each other on the upper surface of the wafer W. Also, theimaging section 76 and the illumination device 75 have rotation axes 90on the lines on the wafer W that intersect each other, and are installedin rotatable members 91 and 92. As the imaging section 76 and theillumination device 75 rotate independently, an image can be taken at anangle suitable for various observation conditions, such as normalreflection, or plus/minus primary/secondary diffracted light.

Moreover, the peripheral edge inspection section 12 is fixed to theloading plate 72. The peripheral edge inspection section 12 is providedin a position where it has retracted from a macro-inspection region D ofthe wafer W shown by an imaginary line. In addition, the movable rangeof the inspection stage 74 in the X-direction is greater than themacro-inspection region D, and is such that the peripheral edge of waferW can enter the recessed part 43 of the peripheral edge inspectionsection 12.

The operation of the present embodiment will now be described. Theinspection stage 74 is made to stand by in a transfer position shown bya position P4, the wafer W is carried into the transfer position by aautomated transport unit that is not shown, and the wafer W is held bysuction-clamping in the inspection stage 74. Next, as the inspectionstage 74 is moved in the X direction towards the peripheral edgeinspection section 12, the linear illumination light from theillumination device 75 is reflected by the upper surface of wafer W, andis introduced into the imaging section 76 for each line, whereby theimage of the whole wafer W is taken.

The control device 45 analyses a difference between an image captured bythe imaging section 76, and a good image that is acquired in advance,and extracts as a defect a region whose luminance difference is morethan a fixed value by image processing. Then, the position of theextracted defect, the information on size, and the classificationinformation in that defects are automatically classified are registeredin a storage unit for every wafer W.

When the automatic macroscopic inspection of wafer W has been completed,the inspection stage 74 is further moved in the X-direction so as toapproach the peripheral edge inspection section 12, thereby making theperipheral edge of the wafer W enter the recessed part 43 of theperipheral edge inspection section 12. In that position, the wafer W isrotated in the θ direction, and peripheral edge inspection is performedsimilarly to the first embodiment. When the peripheral edge inspectionhas been completed, the rotation of the wafer W is stopped, and thenreturned to the position P4 where the wafer W is transferred.

In addition, in this visual inspection apparatus 71, the shift toperipheral edge inspection is made after automatic macro inspection iscompleted. However, the shift to macro inspection or peripheral edgeinspection may be made at any timing by control of the control device45. Further, when the automatic macroscopic inspection has beencompleted, the peripheral edge inspection section 12 may be arranged sothat the peripheral edge of wafer W may enter the recessed part 43 ofthe peripheral edge inspection section 12. The illumination device 75 isarranged rotatably so that even if the peripheral edge inspectionsection 12 is arranged in such a position, such arrangement is allowedif it does not hinder the automatic macroscopic inspection. Moreover,the peripheral edge inspection section 12 may be configured so as to bemovable in the X direction so that the peripheral edge inspectionsection 12 may be brought close to the wafer W after the completion ofthe automatic macroscopic inspection.

In the present embodiment, the peripheral edge inspection section 12 isprovided in the automatic macro-inspection section 73, and theinspection stage 74 of the automatic macro-inspection section 73 is usedfor both the macro inspection and the peripheral edge inspection. Thus,the installation area of the apparatus can be made small. Moreover, theperipheral edge inspection can be performed without transferring thewafer W from the macro inspection, and the traveling distance of theinspection stage 74 can also be significantly reduced compared with acase where separate devices are provided. Thus, the takt time requiredfor inspection can be shortened. Particularly if the inspection stage 74is moved to make the peripheral edge of the wafer W enter the recessedpart 43 of the peripheral edge inspection section 12, it is possible toachieve inexpensive manufacture by only making the inspection stage 74extend in the X-direction. In addition, the effect obtained by providingthe inspection stage 74 and the peripheral edge inspection section 12 sothat they can be brought close to or spaced apart from each other, andthe effect obtained by loading the inspection stage and the peripheraledge inspection section on the same loading plate 72 are the same asthose of the first embodiment. Moreover, the effect obtained byconfiguring the peripheral edge inspection section 12 so as to beattachable to or detachable from the automatic macro-inspection section73 is the same as that of the first embodiment.

In addition, the invention is not limited to the above respectiveembodiments, and can be applied widely.

For example, in the first embodiment, the installation position of theperipheral edge inspection section 12 is not limited to the positionshown in FIG. 1, and may be attached to a side edge of the loading plate30. In this configuration, it is possible to miniaturize a front part ofthe loading plate 30. Even in this case, the peripheral edge inspectionsection 12 is arranged so as to stand by in a position that does notbecome obstructive at the time of micro inspection.

There may be a visual inspection apparatus including only themicro-inspection section 11 and the peripheral edge inspection section12 without having the macro-inspection section 10. Similarly, there maybe a visual inspection apparatus including only the macro-inspectionsection 10 and the peripheral edge inspection section 12 without havingthe micro-inspection section 11. Further, there may be a visualinspection apparatus made up of an automatic micro-inspection section 73and the micro-inspection section 11.

A recessed part that the peripheral edge of the wafer W can enter may beprovided in the microscope 32, and the enlarged image acquisition part44 may be arranged in the recessed part to form a peripheral edgeinspection section. In this case, the space of the micro-inspectionsection 11 can be made much smaller. Further, as long as an arrangementspace exists, a rotating stage and a peripheral edge inspection sectionmay be provided in the position P1, and may be provided in the positionP3.

The workpiece is not limited to a semiconductor wafer, and variousworkpieces, such as a glass substrate, may be used.

Further, a configuration including a variable direction-of-viewobservation apparatus to be described below can be adopted as theconfiguration of the above peripheral edge inspection section. Thisvariable direction-of-view observation apparatus becomes a modifiedexample (hereinafter referred to as a second modified example) includinga concrete configuration of the example of the single-eye type of theabove enlarged image acquisition part 44. In the following, as anexample of the above workpiece, a wafer that is a flat plate-like testbody will be described.

First, the concept of the variable direction-of-view observationapparatus of this modified example will be described.

As for the variable direction-of-view observation apparatus, forexample, an example in which the device loaded into a microscopeapparatus will be described.

As an embodiment of the variable direction-of-view observation apparatusof this modified example, an observation apparatus is used that has aflat plate made up of a wafer, etc. held as a test body (an observationobject or a sample), and that is disposed in the vicinity of a stage ofa microscope apparatus, which is movable and rotatable in triaxialdirections orthogonal to one another, to observe the peripheral end faceof the test body. For example, if a wafer is used as the (flatplate-like) test body, the optical axis of an observation optical system(for example, referred to as an imaging optical system) is arrangedperpendicularly to the principal planes of the wafer. By rotating arotary mirror that placed within the distance from a focus positionuniquely possessed by the imaging optical system to an objective lens,i.e., WD (working distance), thereby changing the observation andinstallation direction (direction of view) of the test body, a mechanismthat always keeps the distance between the objective lens accompanyingthe change of the direction of view and the test body at the above WD isgiven.

This modified example shows a basic configuration of visual inspectionapparatus in which includes an optical system turntable (biaxialstage=ZX stage) on which an observation optical system and a rotarymirror are loaded, a turntable that moves the rotation of the mirror inthe Z direction, and two cams that are engaged with the turntables.

The conceptual configuration of this modified example includes thefollowing a, b, c, d, and e.

a. a biaxial stage that is movable in a direction (Z direction)orthogonal to the surface of a test body and a direction (X direction)parallel thereto;

b. a base having a driving unit that moves the biaxial stage in the Zdirection;

c. an X-direction movable plate of the stage that includes anX-direction cam fixed to the base, a roller engaged with a cam attachedin the X-direction movable plate of the biaxial stage, and a tensionspring acting in a direction in which the base and the X-directionmovable plate (X stage) are brought close to each other;

d. arranging on the X stage an observation (microscope) whose opticalaxis is adjusted at right angles to the surface of the test body, and arotary mirror whose optical axis can be arbitrarily deflected between anobjective lens of the microscope and the focus position of the lens asrequired; and

e. having a mirror cam fixed to the base and a roller engaged with a camattached to a rotary arm protruding from a rotary shaft of the rotarymirror, arranging a tension spring in a direction in which the roller ispressed against the cam between the rotary arm and a bar (spring hook)provided with the X-stage, and always making a focus on the end face ofthe test body by a drive of the base, even if the position of theobservation optical system and the angle of the rotary mirror arechanged by the cam, and the direction of view is moved.

Although this variable direction-of-view observation apparatus may beindependently configured as an inspection (observation) apparatus, theapparatus is attached so that it can hold a wafer on a microscopeapparatus for wafers as a test body, and can be disposed in the vicinityof a stage of the microscope apparatus, which is movable and rotatablein triaxial directions orthogonal to one another, to observe theperipheral end face of a test body held on the stage. Of course, thetest body is not limited to the wafer, as will be described below. Inaddition, in the description explained below, a wafer is used as thetest body, and a planar section in the front and back surfaces of thetest body is called a principal plane. Further, the peripheral end faceof a test body mainly refers to a non-planar peripheral edge of thefront and back surfaces of a test body. Also, if chamfering, etc. isperformed by machining, or if a resist that runs into a surrounding partof a partial rear surface called an edge cut line of a surface fromwhich the resist of the peripheral edge is removed after application ofa resist, the peripheral end surface also includes the above surroundingpart.

Hereinafter, a first mode (hereinafter called a first mode for short) ofthis modified example will be described in detail.

FIGS. 8, 9A and 9B show an exemplary configuration of a first mode of avariable direction-of-view observation apparatus 200. Here, FIG. 8 is aview showing the exemplary configuration when the variabledirection-of-view observation apparatus of the first mode is viewed fromthe front, FIG. 9A is a view showing the exemplary configuration whenthe variable direction-of-view observation apparatus of the first modeis viewed from the side, and FIG. 9B is a view showing an exemplaryconfiguration of a mirror cam as viewed from the arrow A1 (back side ofFIG. 8) in FIG. 9A.

The configuration of this variable direction-of-view observationapparatus 200 will be described. In addition, in the followingdescription, a direction that is the same direction as the principalplane of a wafer used as a test body, and is orthogonal to thetangential line of an end face is defined as an X direction, and adirection that is orthogonal to the principal plane is defined as the Zdirection.

A base 101 in the present apparatus is a plate-shaped member made of ametallic material, such as steel, aluminum, or stainless steel. Thelongitudinal direction of this base 101 is arranged in a directionorthogonal to the principal planes of the wafer 114 used as a test body.

A motor attaching plate 101 a is attached to an upper end of the base101 so as to project in the shape of the letter “L,” and the motorattaching plate 101 a is provided with a motor 102. A rotary shaft (notshown) of the motor 102 rotates in the X direction by a controller thatis not shown. The rotary shaft of the motor 102 is connected with a ballscrew 103 a. The ball screw 103 a is rotatably inserted and fitted intoa ball screw guide 103 b attached to an arm 105 a extending from aZ-movable carriage 105 fixed to the base 101. The ball screw 103 a andthe ball screw guide 103 b constitute a ball screw set 103. By thisconfiguration, the ball screw 103 a is moved by rotation of the rotaryshaft of the motor 102 so as to push up or push down the ball screwguide 103 b.

Further, a rail 104 a that is fixed to the Z-direction movable carriage105, and a case 104 b that is slidably engaged with the rail 104 a andfixed to the base 101 constitute a Z-direction movable linear guide 104.

Furthermore, a cam 108 in which a cam surface 108 a that is curved inthe shape of a recess is formed is fixed to an upper part of the base101 via a plurality of struts. A mirror cam 118 in which a cam surface118 a is curved in the shape of a recess that is different from a camsurface 108 a is fixed to a lower part of the base 101 via a pluralityof struts.

Moreover, a rail 106 a that is fixed to the Z-direction movable carriage105, and a case 106 b that is slidably engaged with the rail 106 a andfixed to the X movable plate 107 constitute an X-direction movablelinear guide 106. By this configuration, the Z-direction movablecarriage 105 by the X-direction movable linear guide 106 and the Xmovable plate 107 by the Z-direction movable linear guide 104 can bemoved two-dimensionally in an X-Z plane.

Further, a cam roller 109 that moves while rotating along the camsurface 108 a of the cam 108 is rotatably fixed to the X movable plate107. A rotary shaft 116 is rotatably provided on the X movable plate107. A rotary arm 119 is fixed integrally so as to extend from therotary shaft 116. A cam roller 117 that moves along the cam surface 118a of the mirror cam 118 that functions as a rotation guide part isrotatably attached to the rotary arm 119. The rotary shaft 116 rotatesby the movement of the cam roller 117 along the cam surface 118 a.

A bar-shaped spring hook 121 a is provided at an upper end of the base101 on the cam 108 side, and a spring hook 121 b is provided at theupper end of the X movable plate 107 opposite to the spring hook 121 a.A tension spring 111 is hooked to the spring hooks 121 a and 121 b. Thecam roller 109 acts so as to always push against the cam 108 by thebiasing force of the tension spring 111. As shown in FIG. 9B, a tensionspring 120 is hooked between a hole of the rotary arm 119, and a springhook 122A provided on the X movable plate 107. The cam roller 117 actsso as to always push against the cam surface 118 a of the mirror cam 118by the biasing force of the tension spring 120.

Furthermore, an imaging section 123 used as an observation opticalsystem that has an optical axis in a direction orthogonal to theprincipal plane of a wafer in a state of being mounted on a rotary tableis provided on the X movable plate 107. This imaging section 123 is madeup of an imaging lens 122, and a CCD camera 112 that receives a lightimage that is focused on the imaging lens 122, and that generates imagesignals by photoelectric conversion. Of course, the imaging lens 122 maybe a configuration made up of an objective lens and a lens that imagesan infinite luminous flux from the objective lens, like a microscope, ora single zoom lens may be used as the imaging lens. Further, a focusingmechanism or a zoom variable power mechanism may be electrically driven.A rotary mirror 115 that deflects the optical axis of the imaging lens122 exists within the WD of the imaging lens, and is bonded to therotary shaft 116 attached to the X movable plate 107.

The operation of the variable direction-of-view observation apparatus200 loaded on the microscope apparatus configured in this way will bedescribed.

The fact that this apparatus always comes into focus even if thedirection of view is changed to the end face of a wafer in the followingorder (even if the rotary mirror is rotated) will be described.

First, referring to FIG. 8, according to an instruction from aninspector (observer), the motor 102 will be rotated by control of acontroller that is not shown. By this rotation, the ball screw 103 a isalso rotated and moved so as to push up or push down the ball screwguide 103 b. If the ball screw is moved so as to push down the ballscrew guide, the Z movable plate 105 is moved so as to approach thewafer 114 along the guide direction of the Z-direction movable linearguide 104.

During this decent, the Z movable plate 105 is moved rightward along thecam surface 108 a such that the cam roller 109 is pushed against the cam108 by the biasing force of the tension spring 111. Simultaneously withthis, the rotary arm 119 is also moved such that the cam roller 117 ispushed against the cam surface 118 a of the mirror cam 118 by the spring120. If the cam roller 117 is moved along the cam surface 118 a, therotary arm 119 will rotate in the clockwise direction.

That is, while the imaging lens 122 descends so as to approach a wafer114 along the Z direction (the direction of an optical axis), it movesin the X direction so as to separate from an end of the wafer 114 in thedirection of a principal plane thereof. In other words, as shown in FIG.8, the end of the wafer 114 and the rotary shaft 116 descend at an equaldistance (WD). At this time, as the rotary arm 119 rotates in theclockwise direction, the rotary mirror 115 also rotates in the clockwisedirection. That is, the shape of the cam surface 118 a is designed suchthat the optical axis of the imaging lens 122 is deflected by the rotarymirror 115, the optical axis always coincides with the end face of thewafer 114, and the distance WD from the imaging lens is kept constantvia the end face and the rotary mirror.

As a result, even if the angle (θ) at which the end face of the wafer114 is observed is changed, a situation where the imaging lens 122 isalways focused on the end face of the wafer can be created. In thisregard, in the present embodiment, the direction of view that allowsobservation is preferably set to about ±45 degrees to the principalplanes of the wafer 114. Substantially, this is because, if thedeflection angle of the rotary mirror 115 is approximately parallel tothe optical axis of the imaging lens 122, the reflecting surface (mirrorsurface) of the rotary mirror 115 should be extremely increased, andtherefore, there is an actual limit to the area of the reflectingsurface of the mirror.

The reason for this will be briefly described with reference to FIGS.10A and 10B.

As shown in FIG. 10A, the positional relationship between the imaginglens 122 and the rotary mirror 115 (θ₂=45°) when the observation fromthe same direction (θ=0) as the principal planes of the wafer 114 isstarted is shown by a solid line, and the positional relationshipbetween the imaging lens 122 and the rotary mirror 115 when an end faceis observed from above is shown by a broken line.

When θ is θ₁, θ₂ is expressed as θ₂=(½)*θ₁. Consequently when θincreases, θ₂ also increases, and thus the reflecting surface coincideswith the optical axis as indicated by a one-dotted chain line, whichwill hinder the observation. Similarly, as shown in FIG. 10B, when theobservation from below the wafer 114 is made, part of the wafer 114 mayenter a space between the imaging lens 122 and the rotary mirror 115,which will interfere with the observation.

Further to describe, the optical axis of the imaging lens 122 will bemost separated from the end face of the wafer 114 when θ=0. It can alsobe appreciated that, as θ becomes large, the optical axis approaches thewafer 114. Consequently, the mirror cam 118 is designed in considerationof these points.

As described above, according to the variable direction-of-viewobservation apparatus 200 of the first mode of this modified example,the rotary mirror 115 is moved in a direction (Z direction) orthogonalto a principal plane with respect to the peripheral end face in the testbody 114 having two principal planes, such as a wafer, while asubstantially constant distance is kept from the peripheral end face ofthe test body 114. Therefore, the distance WD (working distance) to theperipheral end face and the observation optical system becomes constant.As a result, while the end face is observed (imaged), the end face ofthe test body can always be focused.

Further, since the X movable plate that is supporting the imagingsection 123 is moving in the direction of the principal planes of thewafer 114 only to such an extent that the distance WD is kept, thevariable direction-of-view observation apparatus of the presentembodiment is miniaturized. Further, the inspection apparatus is notnecessarily made up of a single unit, and can be disposed and used inthe vicinity of a stage of a conventional microscope apparatus thatholds a test body and is movable and rotatable in triaxial directionsorthogonal to one another. Of course, the observation apparatus can alsobe loaded onto other apparatuses including a stage, without beinglimited to the microscope apparatus for a wafer.

Moreover, various test bodies can be observed by suitably focusing thecurved state of the peripheral end face of the cam surface 108 a, 118 ain the cam 108, 118 to the shape of a peripheral end face of a test bodyto be observed. For example, the cam 108, 118 may be detachablyconfigured so that it can be suitably replaced according to a test body.As a result, even if the cross-sectional shape of an end face of a testbody is a sufficiently rounded shape or a shape the corner of which isslightly rounded, focusing in the imaging section can be made easily.

By providing the peripheral edge inspection section 12 of the visualinspection apparatus 1 of the above embodiment with such a variabledirection-of-view observation apparatus 200, observed images of the endface of the wafer 114 and its front and back surfaces following the endface are led to a microscope of the peripheral edge inspection section12, so that chips or cracks generated in the end face of the wafer canbe detected. Further, in the case of inspection of a mask pattern, theedging state of a resist film, deposition of chemical solution used forforming the resist onto the rear surface of a wafer, etc. can beinspected.

Next, with reference to FIG. 11, an exemplary configuration of avariable direction-of-view observation apparatus of a second mode(hereinafter called a second mode for short) of this modified examplewill be described. In addition, the constituent parts shown in FIG. 11equivalent to the aforementioned constituent parts shown in FIGS. 8, 9Aand 9B are denoted by the same reference numerals, and the descriptionthereof is omitted. While the aforementioned first mode has a limit tothe observation angle (about ±45 degrees), the present mode is anexample in which observation is performed right above or right below atest body. In the present mode, observation of front and back sides ofan outer peripheral part of a test body is allowed by further providingtwo front-and-back observation mirrors as shown in FIG. 11.

In this variable direction-of-view observation apparatus 201, a notch B1is formed in the base 130, and this notch is configured so as to allowentrance of an end of the wafer 114. Moreover, when the end of the wafer114 is inserted into the notch B1, front-and-back observation mirrors131 and 132 fixed to the upper and lower parts, respectively, on theoptical axis (direction orthogonal to the principal plane of the wafer114) are arranged in the positions that recede slightly inward from theend of the wafer.

When observation of an upper principal plane of the wafer 114 is takenas an example, the optical axis in the imaging lens 122 will become thesame as an optical axis deflected by the front-and-back observationmirror 131 if the inclinations of the rotary mirror 115 and thefront-and-back observation mirror 131 are made equal to each other. Thatis, since the optical axis curved by these front-and-back observationmirrors 131, 132 is orthogonal to each principal plane of the wafer 114,it is consequently possible to observe front and back sides of the outerperipheral part of the wafer 114.

In such an arrangement, a cam surface 135 a that extends so as to makethe optical axis from a front-and-back observation mirror coincide withthe optical axis of an imaging lens is provided in a cam 135 incorrespondence with the cam profile in the aforementioned first mode. Byproviding the cam surface 135 a, the angle of a rotary mirror can bedetermined so as to make an optical axis coincide with the optical axisof an imaging lens, in relation to the angle of a front-and-backobservation mirror. The shape of a can surface 134 a is similarly givento a cam 134 so that the sum of L10, L11, and L12 may be equal to WD. Inaddition, when WD is not completely equal to the sum due to anyindividual difference of the wafer 114, etc., it is also possible tocope with this by interposing a stop so as to give a sufficient depth offield to an observation optical system or by installing an AF (automaticfocusing) device.

Alternatively, although a wafer is exemplified as a test body used as anobservation object by the variable direction-of-view observationapparatus of this modified example, the invention is not limitedthereto. For example, by loading a glass substrate used for a liquidcrystal display panel onto an inspection apparatus for the glasssubstrate, it is also possible to observe an end face of the glasssubstrate. Furthermore, the end face of a cut product can also beobserved by attaching the product to a metal cutting apparatus.

As described above, according to the aforementioned first and secondmodes, it is possible to observe the peripheral end face of a wafer usedas a test body from a desired angle, and it is possible to simplyobserve damage, such as chips or cracks generated in the end face andfront and back surfaces over the whole outer periphery of the wafer, oradhering foreign matters, without carrying out focusing work each time.Further, even in this second mode, it is possible to easily attach theobservation apparatus to a microscope apparatus similarly to theaforementioned first mode, and load it into a wafer visual inspectionapparatus, a wafer inspection apparatus, etc. Alternatively, theobservation apparatus may be provided in a substrate processingapparatus that has rotating stages, such as an exposure apparatus, acoater, and a developer.

Next, a variable direction-of-view observation apparatus of a third mode(hereinafter called a third mode for short) of this modified examplewill be described in detail.

In the aforementioned second mode, the front-and-back observationmirrors 131 and 132 are fixed and are turned to a fixed directionregardless of the angle of the rotary mirror 115. Therefore, if lowmagnification observation is set when the end face of the wafer 114 isobserved by the rotary mirror 115, the front-and-back observationmirrors 131 and 132 may enter the field of view of observation of therotary mirror 115. This mode is an exemplary configuration in which,when a movable front-and-back observation mirror is provided to observethe end face of a test body, the observation mirror is made to removefrom the field of view of observation of the rotary mirror 115.

FIG. 12A is a view showing the exemplary configuration when the variabledirection-of-view observation apparatus of the third mode is viewed fromthe front, FIG. 12B is a view showing the exemplary configuration whenthe variable direction-of-view observation apparatus of the third modeis viewed from the back, and FIG. 12C is a view showing an exemplaryconfiguration of a movable front-and-back observation mirror as viewedfrom the arrow C1 in FIG. 12B. In addition, the constituent parts shownin FIGS. 12A, 12B, and 12C equivalent to the aforementioned constituentparts shown in FIGS. 8 and 9 are denoted by the same reference numerals,and the descriptions thereof is omitted.

As shown in FIG. 12A, a variable direction-of-view observation apparatus202 is provided with movable front-and-back observation mirrors 171, 172so that, when the rotary mirror 115 observes the end face of the wafer114, mirror surfaces 171 a, 172 a may be in specified positions thathave depression angles (direction converged on the rotary mirror 115 onthe basis of the direction of an optical axis of the imaging lens 122)of arbitrary angles θ₃, θ₄ with respect to the rotary mirror 115 on thebasis of the principal planes of the wafer 114. The arbitrary angles θ₃,θ₄ are angles provided to prevent the outside light (illumination light,etc.) reflected by the wafer 114 from being reflected again by themovable front-and-back observation mirrors 171, 172, and entering therotary mirror 115. The arbitrary angles θ₃, θ₄ incline slightly withrespect to the front and back principal planes of the wafer 114, and areprovided so as to have a depression angle (an elevation angle withrespect to a wafer principal plane) with respect to the rotary mirror115.

These movable front-and-back observation mirrors 171, 172 have the sameconfiguration, and as shown in FIG. 12B, they are arrangedaxisymmetrically to the wafer 114 (the direction of an optical axis).Between these movable front-and-back observation mirrors 171, 172, adriving plate 173 is provided that is fixed to the X movable plate 107shown in FIG. 9, and rotates any one of the movable front-and-backobservation mirrors 171, 172 along with vertical movement of the drivingplate.

Next, a configuration will be described taking the movablefront-and-back observation mirror 171 as an example.

As shown in FIG. 12C, the movable front-and-back observation mirror 171includes; a mirror body 182 that is rotatably attached to the base 101by fitting a bearing 181 thereinto, a mirror base 183 replaceablyattached to the mirror body 182, a mirror 184 fixed to a tip (the lowerside in this drawing) of the mirror base 183, a stopper part 185provided to specify the aforementioned specified position in the base101, a lever part 186 that is connected and fixed to the mirror body 182via the bearing 181, a cam 188 that is provided at the tip of the leverpart 186 to rotate the mirror body 182 along with the vertical movementof the driving plate 173, and a coil spring 187 that applies a biasingforce that is required for the mirror body 182 to return to a specifiedposition.

As a configuration in which the mirror base 183 is attached to themirror body 182, an attachment surface m of the mirror body 182 isprovided with at least two pins 189 a and 189 b and a screw hole 190,and holes 191 a and 191 b that are fitted to the pins 189 a and 189 b,and a screw hole 191 c are formed in the mirror base 183, respectively.As for the attachment, after the holes 191 a and 191 b of the mirrorbase 183 are respectively fitted to the pins 189 a and 189 b of themirror body 182, a screw 192 is screwed into the screw hole 190 throughthe screw hole 191 c. As such, since the mirror base 183 has adetachable configuration, even if a mirror becomes dirty, it can beeasily cleaned.

The stopper part 185 includes a stopper column 193 fixed to the base101, and a stopper 194 that defines a specified position where the leverpart 186 is locked. The coil spring 187 has one end hooked to the leverpart 186, and the other end hooked to the base 101, and the biasingforce of the coil spring is applied so that the lever part 186 mayalways be pressed against the stopper 194.

Next, with reference to FIGS. 13A to 13G, the operation of the movablefront-and-back observation mirrors 171, 172 configured in this way willbe described. In this example of observation, the lower surface of awafer is observed via an end face from the upper surface of the wafer.

FIG. 13A shows a state where the upper surface of the wafer 114 isobserved from the front of the apparatus, and FIG. 7B shows therotational state of the movable front-and-back observation mirrors 171,172 viewed from the back. In this observation state, the rotary mirror115 is located higher than the movable front-and-back observation mirror172, and the cam 188 of the movable front-and-back observation mirror172 is pulled up by the driving plate 173. Then, the front surface(upper principal plane) of the wafer projected on the movablefront-and-back observation mirror 172 is projected via the rotary mirror115 so as to run along the optical axis of the imaging lens 122. At thistime, the movable front-and-back observation mirror 171 is in a freestate, is biased by the coil spring 187, and is held at the arbitraryangle θ₃ so that the surface of the mirror may be in the aforementionedspecified position.

Moreover, when a peripheral end face of the wafer 114 is observed from adirection substantially vertical to the normal line of a surface of thewafer from the state shown in FIGS. 13A and 13B, the rotary mirror 115is pressed down while rotating, resulting in the observation of the endface of the wafer 114 (refer to FIGS. 13C and 13D). In the state wherethis end face is observed, the cams 188, 195 of the movablefront-and-back observation mirrors 171, 172 are not in contact with thedriving plate 173, but in a free state. For this reason, the movablefront-and-back observation mirrors 171, 172 are together in a freestate, are biased by the coil spring 187, and are held at the arbitraryangles θ₃, θ₄ so that the surface of the mirror may be in theaforementioned specified position.

At this time, as shown in FIG. 13E, the mirror 184 of the movablefront-and-back observation mirror 171, 172 is put into rotation, so thatit cannot enter the field of view of observation of the rotary mirror115.

In this observation state, the rotary mirror 115 is pushed down whilerotating, and is thereby located lower than the movable front-and-backobservation mirror 171, and the cam 195 of the movable front-and-backobservation mirror 171 is pulled down by the driving plate 173. Then,the rear surface of the wafer (lower principal plane) projected on themovable front-and-back observation mirror 171 is projected via therotary mirror 115 so as to run along the optical axis of the imaginglens 122. At this time, the movable front-and-back observation mirror172 is in a free state, is biased by the coil spring 187, and is held atthe arbitrary angle θ₃ so that the surface of the mirror may be in theaforementioned specified position (refer to FIGS. 13F and 13G).

As described above, according to this mode, by rotating one of twomovable front-and-back observation mirrors that are arranged vertically,with movement of a rotary mirror, an observed image of the front surfaceor rear surface of a test body can be guided to the optical axis of animaging lens by the rotated movable front-and-back observation mirrorand the rotary mirror. Further, when the end face of a test body isobserved, both the movable front-and-back observation mirrors areretracted from a field of view of observation. It is therefore possibleto provide an easily viewable observation image in which only the testbody used as an observation object exists within a field of view ofobservation. Further, even in this third mode, it is possible to easilyattach the observation apparatus to a microscope apparatus similarly tothe aforementioned first mode, and load it into a wafer visualinspection apparatus, a wafer inspection apparatus, etc.

In addition, the variable direction-of-view observation apparatus 202 ofthis mode is made in consideration of both the visual observation byobserver's direct viewing and a monitor image using an imaging device.However, the invention is not limited to this third mode. For example,in the case of a configuration in which only the monitor image isobserved, observation can also be realized by removing an image of thefront-and-back observation mirror that has entered from a picked-upobservation image, or by generating an image without fetching an imagesignal equivalent to a front-and-back observation mirror from an imagingdevice.

Although the description of the above second modified example has beenmade in conjunction with an example of the case in which the variabledirection-of-view observation apparatus of each mode is loaded into aninspection apparatus, such as a microscope, that is, the apparatus isincluded in the peripheral edge inspection section of the visualinspection apparatus of the invention, the variable direction-of-viewobservation apparatus of each of the above modes can also be preferablyused as a single unit as an observation apparatus in which the directionof view to a test body is variable.

The background art in this case will now be described.

For example, JP-A-9-269298 (Patent Document A), and JP-A-2003-344307(Patent Document B) discloses an end defect inspection apparatus thatexclusively inspects the end face of a wafer in order to detect chips,cracks, etc. generated in the end face.

The following problems exist in the background art.

In the aforementioned wafer edge inspection, generally, in order todetect chips, cracks, etc. of the end face of a wafer, detection is madeby visual observation of an image that is obtained by imaging a waferedge over its whole outer periphery, or by the change of a detectionvalue that is obtained by photoelectric conversion.

Since the end defect inspection apparatus according to Patent Document Ais configured so as to detect chips, cracks, etc. from part ofdiffraction light from the end face of a wafer, it is not possible toobserve the front surface or rear surface that leads to the end face ofthe wafer. Similarly, even in the defect inspection apparatus disclosedin Patent Document 2, it is not possible to detect chips, cracks, etc.of a front or rear surface that leads to the end face of a wafer.Further, in both Patent Documents A and B, it is not possible to performobservation of an edge cut line after the resist of an edge part on thefront side is removed. Further, the same applies to a glass substrateused for a liquid crystal display. In this case, it is necessary toperform optimal processing while checking damage, such as chips orcracks generated in an end of the glass substrate, an unnecessary film,etc.

Thus, a variable direction-of-view observation apparatus that canobserve a peripheral end face of a test body (end face, and front andrear surfaces of an outer peripheral edge following the end face) from adesired angle has been required.

Such a variable direction-of-view observation apparatus is provided bythe following configurations.

(1) A variable direction-of-view observation apparatus including anobservation optical system that observes a peripheral end face of a flatplate-like test body, and a mirror part that deflects an optical axis inthe observation optical system, to make the optical axis reach theperipheral end face of the test body. Here, while the direction of viewis changed by the rotation of the mirror part, the distance between theobservation optical system and the peripheral end face of the test bodyremains substantially constant, and the peripheral end face of the testbody is observed.

(2) A visual inspection apparatus including: a base part that is fixedin a position where the peripheral end face of a flat plate-like testbody can be observed; an observation optical system that has an opticalaxis orthogonal to the surface of the test body; a biaxial stage thatsupports the observation optical system, and is movable in directionsorthogonal and parallel to the surface of the test body; a mirror partthat is rotatably supported by the biaxial stage to deflect the opticalaxis in the observation optical system, to make the optical axis reachthe peripheral end face of the test body; and a rotation guide part thatis provided in the base part, abuts and biases the mirror part so as toallow sliding of the mirror part, and rotates the mirror part so thatthe optical axis in the observation optical system may be deflected andmay be made to reach the peripheral end face of the test body at thetime of movement of the orthogonal direction in the biaxial stage. Here,while a direction of view is changed by the rotation of the mirror part,the distance between the observation optical system and the peripheralend face of the test body remains substantially constant, and theperipheral end face of the test body is observed.

(3) The visual inspection apparatus according to the above (2), in whichthe base part of the variable direction-of-view observation apparatusholds the test body, and is disposed in the vicinity of a stage of amicroscope apparatus that is movable and rotatable in triaxialdirections orthogonal to one another.

(4) The visual inspection apparatus according to the above (2), in whichthe rotation guide part of the variable direction-of-view observationapparatus includes a first cam that is provided in the base part, andhas a cam surface that is curved so that the mirror part may have asubstantially fixed spacing from the peripheral end face of the testbody during the movement in the orthogonal direction of the biaxialstage; and a first cam roller that slides along curving of the camsurface at the time of movement of the orthogonal direction of thebiaxial stage, and that rotates the mirror part so that the optical axisof the observation optical system may reach the peripheral end face ofthe test body.

(5) The visual inspection apparatus according to the above (2), in whichthe variable direction-of-view observation apparatus further includes astage guide part made up of a second cam that is provided in the basepart, and has a cam surface that is curved so that the optical axis inthe observation optical system may be maintained in a directionorthogonal to a surface of the test body in the rotation guide part withthe movement in the parallel direction at the time of movement of theorthogonal direction of the biaxial stage; and a second cam roller thatis provided in the biaxial stage and slides along curving of the camsurface at the time of movement of the orthogonal direction.

(6) The visual inspection apparatus according to the above (2), in whichthe variable direction-of-view observation apparatus is further providedwith two fixed mirrors that are fixed to the base so as to be arrangedabove and below the front and back surfaces of the test body, and bendsthe optical axis of the observation optical system in the direction ofthe peripheral end face of the test body.

(7) The visual inspection apparatus according to the above (2), in whichthe variable direction-of-view observation apparatus is further providedwith two rotary mirrors that are fixed to the base so as to be arrangedabove and below the surface of the test body, bends the optical axis ofthe observation optical system in the direction of the peripheral endface of the test body, and are set at a predetermined angle duringobservation from above or below.

(8) The visual inspection apparatus according to the above (2), in whichthe variable direction-of-view observation apparatus is further providedwith two rotary mirrors that are rotatably arranged in the base so as tobe arranged above and below the test body. Here, when the upper surfaceor lower surface of the test body is observed, any one of the rotarymirrors is rotated, and an observed image of the test body enter theobservation optical system via the mirror part, and when the peripheralend face of the test body is observed, the mirror surface of the rotarymirror is set to have an angle of depression with respect to the rotarymirror, and is removed from the field of view of observation in theobservation optical system.

(9) A visual inspection apparatus is an observation apparatus loadedinto a microscope apparatus that observes the surface of a flatplate-like test body. The observation apparatus includes: a biaxialstage that is movable in a Z direction orthogonal to the surface of thetest body, and in an X direction parallel thereto; a base having adriving unit that moves the biaxial stage in the Z direction; a parallelmovable plate of a stage made up of a first cam fixed to the base, aroller that is attached to an X-direction movable plate of the biaxialstage, and moves along the first cam, and a tension spring that acts ina direction in which the base and the X-direction movable plate arebrought close to each other; an observation optical system of themicroscope apparatus whose optical axis is orthogonal to the surface ofthe test body on the biaxial stage; a mirror part that is arrangedbetween an objective lens within the observation optical system and thefocusing position of the objective lens, and is able to arbitrarilydeflect the optical axis; a second cam fixed to the base; a secondroller that is attached to a rotary arm protruding from a rotary shaftof the mirror part, and moves along the second cam; and a tension springthat is hooked between the rotary arm and the biaxial stage, and acts ina direction in which the second roller is pushed against the second cam.Here wherein, even if the position of the observation optical system andthe angle of the rotary mirror are changed according to the first andsecond cams with the movement of the biaxial stage in the Z direction,thereby arbitrarily changing the direction of view, the distance betweenthe objective lens and the peripheral end face of the test body remainsconstant while the direction of view is changed with respect to theperipheral end face of the test body and the front and back surfacesfollowing the peripheral end face.

In the variable direction-of-view observation apparatuses described inabove (1) to (9), even if the position of the observation optical systemand the angle of the rotary mirror are changed by the rotary guide part,thereby changing a direction of view, observation can be made whilefocusing is always made on the peripheral end face of a test body, andthe principal planes (upper and lower surfaces) following the peripheralend face. Therefore, it is possible to provide a variabledirection-of-view observation apparatus that can observe a peripheralend face of a test body (end face, and front and rear surfaces of anouter peripheral edge following the end face) from a desired angle.

1. A visual inspection apparatus comprising: a visual inspection sectionfor performing visual inspection of a surface of a workpiece; aperipheral edge inspection section that acquires an enlarged image of aperipheral edge which includes a side part, a chamfered part of aworkpiece, and a surrounding part of front and back surfaces of theworkpiece; and a holding unit that is configured to hold the workpieceand that is capable of moving, the holding unit being provided in thevisual inspection section; wherein the holding unit is shared between aninspection at the visual inspection section and an inspection at theperipheral edge inspection section by moving between the visualinspection section and the peripheral edge inspection section.
 2. Thevisual inspection apparatus according to claim 1, wherein the holdingunit and the peripheral edge inspection section are provided so as to bebrought closer to and spaced apart from each other.
 3. The visualinspection apparatus according to claim 1, wherein the peripheral edgeinspection section is detachably provided in the visual inspectionsection.
 4. The visual inspection apparatus according to claim 1,wherein the visual inspection section includes a micro-inspectionsection that acquires an enlarged image of the surface of the workpiece,and wherein the holding unit is shared so as to be movable between themicro-inspection section and the peripheral edge inspection section. 5.The visual inspection apparatus according to claim 4, further comprisingmeans for: (i) recording a coordinate of an observation position wheninspection is performed in one of the micro-inspection section and theperipheral edge inspection section, and (ii) moving the observationposition to an observation position of the other one of themicro-inspection section and the peripheral edge inspection sectionbased on the recorded coordinate of the observation position wheninspection is performed in the other one of the micro-inspection sectionand the peripheral edge inspection section.
 6. The visual inspectionapparatus according to claim 1, wherein the holding unit and theperipheral edge inspection section are provided on a same loading platethat is free from vibration.
 7. A visual inspection method comprising:holding a workpiece by a holding unit provided in a visual inspectionsection, and visually inspecting a surface of the workpiece; bringing aperipheral edge inspection section that acquires an enlarged image of aperipheral edge which includes a side part, a chamfered part, and frontand back surfaces of the workpiece closer to the holding unit; andacquiring the enlarged image of the peripheral edge of the workpiece ina state where the holding unit is brought closer to the peripheral edgeinspection section.
 8. A peripheral edge inspection unit that ismountable on a visual inspection apparatus, the peripheral edgeinspection unit comprising: an anchor which is detachable from a visualinspection section that performs visual inspection of a surface of aworkpiece in a state where the workpiece is movably held by a holdingunit; and an enlarged image acquisition part that is arranged so as toface a peripheral edge which includes a side part, a chamfered part, andfront and back surfaces of the workpiece held by the holding unit, andthat is capable of acquiring an enlarged image of the peripheral edge ofthe workpiece.
 9. The peripheral edge inspection unit according to claim8, wherein the anchor and the enlarged image acquisition part areconnected via a uniaxially movable stage.
 10. The visual inspectionapparatus according to claim 1, wherein the workpiece is a flatplate-like test body, and the peripheral edge inspection sectionincludes: (i) an observation optical system that observes a peripheralend face of the flat plate-like test body, and (ii) a mirror part thatdeflects an optical axis in the observation optical system to make theoptical axis reach the peripheral end face of the test body, andwherein, while a direction of view is changed by rotation of the mirrorpart, a distance between the observation optical system and theperipheral end face of the test body is kept substantially constant, andthe peripheral end face of the test body is observed.
 11. The visualinspection apparatus according to claim 2, wherein the peripheral edgeinspection section is detachably provided in the visual inspectionsection.
 12. The visual inspection apparatus according to claim 11,wherein the visual inspection section includes a micro-inspectionsection that acquires an enlarged image of the surface of the workpiece,and wherein the holding unit is shared so as to be movable between themicro-inspection section and the peripheral edge inspection section. 13.The visual inspection apparatus according to claim 12, furthercomprising means for: (i) recording a coordinate of an observationposition when inspection is performed in one of the micro-inspectionsection and the peripheral edge inspection section, and (ii) moving theobservation position to an observation position of the other one of themicro-inspection section and the peripheral edge inspection sectionbased on the recorded coordinate of the observation position wheninspection is performed in the other one of the micro-inspection sectionand the peripheral edge inspection section.
 14. The visual inspectionapparatus according to claim 2, wherein the visual inspection sectionincludes a micro-inspection section that acquires an enlarged image ofthe surface of the workpiece, and wherein the holding unit is shared soas to be movable between the micro-inspection section and the peripheraledge inspection section.
 15. The visual inspection apparatus accordingto claim 14, further comprising means for: (i) recording a coordinate ofan observation position when inspection is performed in one of themicro-inspection section and the peripheral edge inspection section, and(ii) moving the observation position to an observation position of theother one of the micro-inspection section and the peripheral edgeinspection section based on the recorded coordinate of the observationposition when inspection is performed in the other one of themicro-inspection section and the peripheral edge inspection section. 16.The visual inspection apparatus according to claim 3, wherein the visualinspection section includes a micro-inspection section that acquires anenlarged image of the surface of the workpiece, and wherein the holdingunit is shared so as to be movable between the micro-inspection sectionand the peripheral edge inspection section.
 17. The visual inspectionapparatus according to claim 16, further comprising means for: (i)recording a coordinate of an observation position when inspection isperformed in one of the micro-inspection section and the peripheral edgeinspection section, and (ii) moving the observation position to anobservation position of the other one of the micro-inspection sectionand the peripheral edge inspection section based on the recordedcoordinate of the observation position when inspection is performed inthe other one of the micro-inspection section and the peripheral edgeinspection section.